Telephone system.



'PATENTED MAY 1 W. W. DEAN. TELEPHONE SYS'lT-Iifi.v APPLICATION FILED NOV 11 1903 I -H l l T l lmw l F11 )1. din

3E nYSEEM.

jrpgilicnticn filled liovember 11, 1902 all whom it may concern:

Be it known t l, Wuiiiniir W. DEAN, citizen of the Unit .d States of America, and resident of Chic-ego, county of Cook, and State of lllinois, h ve invented uscl'ul linproveznei Tclep Systems, oi which the toliow bi'ttllfil.

relates to lone systems of the common be 3' type, and more per tiuilurlv 'r of sources current the control oilice provided, one of i being connected with the culling line stud other with the celled lines during corwersetion. it been common. lierotoforc'iu suhsc;'.bers lines of the letter type to disconnect the outcry from the line when connection was established with cell ing lines, thereby causing noise in the wait ing subscribers receivers to such an extent as to result in considerable annoyance to them, I

,ldy iuvention'hss for one of its objects to obviate to at great degree, if not entirely, the noise in the waiting subscribcfs receiver, end this is preferably accomplished by not severing the normal connection of the central source of current therewith when the operetor connects her cord circuit with the line in response to tho subscribcrs call. in co1n pleting the connection for conversation, 1 preferably so uge the epp otus that the second source current connected with the called line, so that the two lines are sup plied with current ior talking from the tvm batteries.

A furtherv object oi" the invention. is to thus apply the second lurttery to the called subscribers lines through the medium the My inventi cord circuititself.

Gt-her objects to simplify the apparatus required for systems of tl's t 1c, and to produce a. thoroughly onerstr s end cilicicnt system with the is complication and edditiouel expense possiols.

Still further objects end advantages of the system will hcreineite appear.

lvly invention is illustrated in the accompanying drawing in which the 'ilgure is a dia gram of s telephone embodying my improvements.

in this figure, scribers lines A from their I L t i and L" indicate two sub- .enoing in tw limbs 2 end 3 s A end 1) to "l the eet-ion. of lhettsrs Futont.

s new and l from.

Batented May 12, loos.

Serial No. 180,685.

denser 5 in a. permanent bridge of the lineconductors, end a trensriutter 6, the receiver 7 in a second bridgeof sold conductors th at is normally held open at the switch book 8 by the weight of the receiver suspended there- This arrangement is intended merely to be typical of any usual or desired common battery outfit.

At the central oiiicc the subscribcfs line is provided with the usual linc signal S, on answerin jock d and a plurality of multiple jsclas sucn as J and J in any desired number, according to the capacity of the multiple switchboard upon which they are located. The telephone line is also fitted with a line relay ll and with c cut-oil relay R the latter being included in the sleeve line conductor 3, while the ioru'ier is provided with windings 9 and 10, the former being logged to ground from the line conductor 3, while the letter is connected between the line conductor 2 and the spring 11 of the cut-oil relay R", the norincl contact of said relay being electrically united through the medium. of a conductor 12- with the common battery load or omnibus bar 13 connected with the live pole of the central common battery B. The said cutoil' relay R is provided with an additional spring 14, the normal contact of which is connected by a. branch conductor 15 with said wire 12 end is itself joined by a conductor 16 with one side of the line signal S which is preferably in the form of a snurll incandescent lamp. The other terminal of said signal is joined by u conductor 17 with the sprin of the line relay ll, the forward contact or which is grounded.

The operator s outfit comprises a plurality of cord circuits, one only being shown and each cord circuit I including an answering plug l? end a csllin'g plug P having tip and sleeve contacts adopted to register with the corresponding contact surfaces of the spring oi the lines when inserted therein. The tip contacts of said plugs are united with the flexible strands t and t and the interposed condenser c, whilc the sleeve contacts thereof are similarly joined by the strands s and s end the interposed condenser cuit, a pair of supervisory relays r and r are bridged, the former controlling throu h its normally closed contacts and the letter through normally open contocts the lOCtIl circuit of the supervisory signal S associated with the answering lug PI An intermediate oint of said bri ge is joined by branch con uctor 18 with the said battery lead 13.

A second pair of supervisory relays r and r suitable condenser c are adapted to bebridged across the calling end of the cord circuit by the springs 22 of any suitable listening liey, her transmitter 23 and theprimary of her induction coil being charged from any suitable source of current which may be either the battery B or B The supervisory relay 7* is provided With an additional spring 24 connected with the forward portion of the strand t of the cord circuit and is adapted, upon the operation of v the su ervisory relay to complete the said strano t for conversation; under normal conditions, the said forward portion of the strand is connected with a conductor 25 leading to an extracontact 26 upon the operators listening key. When the listening he is operated, the spring 26 is connected wit the high resistance and high impedance test relay r that is preferably common to all the cord circuits of the operators position, as is indicated by the branching lines from the point 27. This relay 1' controls through its normally open contacts and the branch conductor 28 a local circuit containing the tertiary Winding of the operators induction coil 21, and connected with the common wire 29 leading from the live pole of the battery B A suitable ringin generator 30 is ada ted to be connected with the tip side of the ine by the operation of the ringing key springs 31, 31, the sleeve side of the cord circuit being at the same time connected by conductor 32 with the live pole'of the battery B In order that the calling subscribers shall be rovided with current from one battery an the called subscribers with current from.

the other battery, '1 preferably make the supervisory relays r and r associated with the answering end of the cord circuit of hi h resistance, say 5000 ohms each, while t e corresponding pair of relays, namely r and 7" may be respectively of 100 and 500 ohms resistance. The line relay windings 9 andlO may be of 100 ohms resistance, and the cutoff relay R should be of such resistance that it will not be actuated sufiiciently to lift the spring 11 from its normal contact when con nected in series with the answering end ofthe su JGI'Vl-SOIY relay 1' but will be actuated in y to lift the said spring 11 fromits normal contact whenever connected in. circuit' with earner the sleeve supervisory relay r associated with the calling and the cord circuit. The electrical dimensions'ot' the other parts of the apparatus may be such as are ordinarily used. hr as preferred.

The operation of my invention is as iolloWs:-Pissuining that the subscriber A de sires to converse with subscriber D, he takes up his receiver, thereby closing the path for current from the battery l3, over conductors 13 and 12, spring 11, the winding 10 of the line relay R, line conductor 2, through the substation device and thence back to the central oflice over line conductor 3 and through the winding 9 of said. line relay R to ground. The current flowing in this path actuates the line relay it and closes the local circuit of theline signal from the said bat tery lead 13 through conductors 12 and 1.5,

spring 14 of the cut-off relay R conductor 16, through the said lamp conductor l7 and.

the closed contacts of said line relay it to ground. The signal is thus lighted and upon observing the same the operator inserts the answering plug P of her cord circuit in the answering ack J of the calling telephone line and connects her'instruinent with the cord circuit through the medium of her listening key 22/ The insertion of the plug l? closes a path of current from the battery B over vconductors 13 and '18, through the sleeve supervisory relay r which is of high resist ance, the strand 8 ol the cord circuit, sleeve contacts of the lug and jack, and thence over the line con uctor 3 including the Winding of the cut-oil relay R and through the Winding 9 ofthe line relay it to ground. Owing to the high resistance of the supervisory relay 7*, the said cut-oil relay R is actuated only su'fliciently to remove its spring -14 from the normal contact, thereby opening the circuit of the line signal S and retiring the same. The spring l], er said relay is not now lifted from its normal contact so that the current from the battery B continues to be supplied to the telephone line L over the path just traced for thevcondition when the subscriber .was calling the central oflice. In addition to this path for current through the winding 10 of the line relay R, there is a parallel ath through the conductor 18, the tip strand cuit and thence over the line conductor 2 to the substation. This supervisory relay thus receives sufiicient current to actuate the same to open the local circuit of the supervisory signal A Which in consequence remains unlighted. it is thus a parent that the battery current is mainly ed to the substation through the path originally traced and that the change of potential upon'the line remains t of the cord'cirpracticallyccnstant during the operation of connecting the cord circuit therewith so the subscriber is not disturbed by noise n1 his receiver.- i- I Upon learning the order of the subscriber wanted, his line is tested in the usual manner to determine its idle or busy coiulition. it will be observed that the test contacts of the lines are normally grounded through the winding l? of the line relay ll and since the tip of the calling and testing plug: is likewise grounded. through the test relay r by reason of the supervisory relay 7- not yet being opersted and the listeninglcey 22 being depressed, no liow of current results and the operator knows that the line idle. in case the line is engaged, however, said test rings are connected through the sleeve strand 5: or s of theinserted plug with the live pole of either the bntt ry B or B and when the grounded tip of the plug is brought into contnct therewith, a How of current results suilicient to actuate the test relay 7 which closes the local circuit throu h the tertiary Winding in the operutors ind uction coil, and thus causes a click in her receiver, thereby notify ing her that the line is busy. Assuming that the line is found idle, the csllin plug P is inserted in the multiple jack of the line be fore the operator, and the ringing key 31 is depressed. The not of inserting the plug i closes circuit over the conductor 1%? and through the sleeve, supervisory relay 1, whicl'i is of less resistance then r and of nter icsistnncc thnn the sleeve strnnd of the cord circuit, the sleeve side i; of the through the culroll' relay old line, and thence to ground through a 'ing 9 of the line relay ll. The current in this path, owing to its low resistance, is sulficient to fully actuate said cut-off relay il to cause it to t only open the local 0 unit of the line signal S, but nlso lift the spring ll of said relay from its nor nul contsct, thereby opening: the normal connection with the battery 3. The depre sion of the ringing: hey connects the geiuirulgor ill with the tip side of the line therohy sendi the ringing; current out to the substation i l operating the signalling; bell thcront, and thence returns to the central ollicc "through the sleeve strund oi the cord circuit, the conductor 32, common wire ill and through the l)" to grouluh At the some time curoui the l'nrttcr Pf through said conductors 29 and I l-snpplying current for the continued ops-i .tlon oi the cut--oll rchiy ll, which thus prevents false signals in, the answeri; 9, section of lhe suitchbonz'd upon which the calling signal of said line located. As soon as the subscriber has been called, but before his respo'i'ise, the supervisory relay r is actuated over the path lust traced and closes the local circuit oi the supervisory signal 55 which is lighted, and inuicntes lo the operator the condition oi the walled subscribers tele hone. cord circuit is likewise now completed "for conversation through the spring 24 of said The strand t" of the l l l l supervisory relay and wlicn'thc subscriber answers by taking up his receiver, current llmys from said bntlcry B through the supervisory relay 1', thenclover the strand 15 and the tip side of the line to thy substation, with return over the linc conductor 3, and through the. winding 9 ol the linc relay. thus 'nctunl'iirg the supervisor) relay r nnd retirin; the signal S? During -onversntion, therefore, the battery B is furnishing current to the line L lor conversntii'm, and the buttery B is furnishing current to the line if for Av similar purpose. Thus the lines are independently supplicd with operating current from said batteries B and ll". ll will be ob served that the spring '14 ol' the cut-oil relay it" is insulated lrom the spring H by the small piece ol' insulation mounted upon tho end of the'lutter.

Having thus described my invention in one commercial form what l-clnim is:"

l. in n telephone system, the combilnr lion with a plurality of telephonilims, of u pair of sourccsof current at the central ollicrto furnish current over said lincsl'or conversation 2L cut-oil relay for ouch line, one ol' said sourccs of current being normally con nected with the lines to furnish currenl thercovcr while the subscribers are calling! tho control ollicc, an operators cord circuit means for actuating said cut-oil relays in one nnmncr when the cord circuit is connected with the fivllllll" subscribcrs line to render the line signals oi said lines inoperative and to leave the connection of said source with said lines undisturbed, means for operating the cut-oil relays in a different manner when the cord circuit is connected with the called. lines to not onlyirendnr the signals of said lines inoperative during connections but to also disconnect the said source from the sold lines and menus to at the same time connect the other of said sources to the bitter lines to furnish current thcreover for con vc'rsntion, suhstmitiolly as described.

2. in a. telephone systcn'i, the combination with a plurality of telephone lines, of a pair of sources of current n: the central ollice, one ol' which is normally connected with said lines to furnish current l'hcreoyer when the suli i opt n .lrs connective circuit for establishing connections between the lines for conversm lion, :1 (-nt-oll' relay for each line adapted when only gnn-ixinllyoperated to render the ribcr car ling the central ollicc, on-

line signal ino 'lorativc and when Wholly operatcd lo rcnd r said signal inoperative and at the some time sever the normal connectron oi sand source, and means whereby when.

the sold cord circuit is connected with tho ea /e71 time connected "with the said called lines, 1 the cut-oil" relays and other parts included in substantially as described.

3. In a telephone system, the coinhim'rtion with a plnrslity of tele hone lines each bar-- ing a line signal, of cut-oil relay for each line, a pair of sources of electricity one of which is normally connectet Withthe lines to enable the subscribers to call the central o'llice, a cord cirmlit to connect the lines together for conversation, a circuit established through the said cut-off by the cord circuit when connected with. the lines, a hieii resistance included in the circuit so cstanlished by one end of the cord circuit and a low resistance included in the circuit established by the other'end of the said cord cirl cult whereby in each complete connection the normally connected source remains con nected with one line and is cut oil from the other, and means for connecting the second source tothe latter line, substantially as described.

4-. ln a telephone system, the combination with a plurality of telephone lines each having a line signal, of a cut ofl relay for each line, a pair of sources of electricity one of which is normally connected with the line to enable the subscriber to call the central ollice, s cord circuit to connect the lines together for conversation, acircuit establisln-vd through the said cut--oll relays by the cord circuit when connected with the lines, it high resistance corn'iected with the answering; end of the cord circuit and. a, low resistance with the calling end, and means whereby "whei'i' the cord circuit establishes connection between two lines the high resistance device is included in circuit with the cut-oil relay of the calling line to pert-nit said normally connccted source to remain in connection there with and said. 10W resistance device is connected in circuit with the cut-oil rel ay oil the called-for line to permit said relsyto be operated and thereby to disconnect said source, the second. source of said pair being at the same time placed in connection with the latter line substantially as d scribed.

in a tel :36 s stem, the combination with a plurality oi tcliepl'ione lines o .h new ing a line; signal and neat-oil reisy, of s neir of sources of clectricit" with one which said lines are normally connected through contacts of the cut-oil relays, s cord circuit to establish connections between the lines conversation, a high resistsneedevice con-- nected with the answering end of cord circuit snd adopted to be included local circuit with the cut-oil relay when conned tion is established. with s calling and a low resistance device connected with the calling end of the. cord circuit and adapted to be si milnrl y connected in a local circuit with the cut-oil relay of the called. line when the calling cord is connected therewith, said rc- Sistejnccs being so proportioned relatively to the local circuits that the cut-oil relay of the calling line 1s actuated only suliiclently to rendcr the, line signal inoperative, the normally connected source rmnaining in connection with said line, and the cutoil rein-y of the called hnc to be completely operated to rcn-- der the line signal inoperative and to sever the connection of the normally connected source therewith and. means for at the same time connecting the second source with the lstter line, substantially as described.

6. in a telephone system, the combination with s plurality of telephone lines each having a line signal and a cut-oil relay control.- ling the circuit of the signal, of a pair of sources of electricity with one of which said lines are normally connected to enable the subscribers to call the central office, a cord circuit, means for completing; a, local circuit through the cut-oil relays of the lines when the cord circuit is connected. therewith, a high resistance supervisory relay associated with the answering end of the cord circuit and adapted to be included in said local cir cuit during a connection, it low resistance supervisory relay connected with the callin end of the cord circuit and likewise sdspte to be include oil rein-y or" the called line during it connection, the resistnnce of ssid relays being so ad insted that the cut-off relays of the calling lines are actuated only suilieiently to-render the line signals inoperative and to permit the normally connected source to remain in 0011-. nection tl'iercwith While the cut-ofi relays of the called lines are fully actuated to render the line signals inoperative and to disconnect said normal current source, and means for st the same time connecting the second source of current with the letter line, substantially as described.

7. In a telephone system, the combination with a plurality or telephone lines, oi a source of current at the central ofiiec normally connected with said lines to furnish current for signaling, a cord circuit, and s second source associated therewith, n'ieans during conversation to furnish transmitter current lrorn said first source only to the calling telephone line and from the second source only to the called telephone line, substantially described.

8, In a telephone system, the combination with a plurality of telephone lines, of line signals and cut-oli relnys tlwrel or, a source of current normally connected witl. the lines through contacts oi the cuboil relays to prowide current for signaling "the central otlice from the substations, answering and multiple jacks connected with the lines all having the same sire-int relation to the cutmfl relays, a cord circuit, means associated with the cord in the local. circuit of the cutcircuit for suitably controlling said cut-oil re;

lays whereby when connection is established with the ansviei'ingend of the cord the ouirofif rehiy is operated to render the corrosponding line signal inoperative but not to sever the commotion of said sourceand when connao Lion established by the coiling ozmti oi the cord cii'ouit the out-off reioy of the zine 50 connected is operated to not only T811016? tho iine signal inoperative. but to aiso disconneoiz said source, and a. second source izonnectsd' with the latter lines, si ibsmiitiiiiiy $33. dew scribed.

9. In a teiephonelsystem, the fifili'fiifi infi ifliQil with a plurality of telephone lines, of a source of current with which the lines are noz'miiiiy connected, a, cord circuit, means when oo ir nection is osm biished by one and of tho cord circuit whereby gaid souroe remixin in cow nection with the line and alone feedsain't-om thereto for conversation, a seoomi soiiifoo of current, and means when the (ii-hm and of the cord. oiruuit is comm/chad to the ssoond 5 ime whereby current from said second assume is fed to the second line ohiy through said cord circuit, substantially 52s doscrihmii 10. In a telephone syatom, the com tion with a. plurality of tele hone iines. cord circuit to connect said ines for on; sation, of two sources of direoicurrent fox onorgy a y m, oombiimzion with ii, phiof "oiophoiie iiiies, of two sources of mm i'ei 10; said iine-s at tho control offioe, means whwehy energy :hom one of amid sources mo be normally maintained on all of said iines, and. .fuifliei" means when twoiiiies'aro placed; in oomi iigioli conversation whereby one of lines will receive talking Gillieni? only from one of sourcs, and whereby the other of mid iii'ies Wiii roceivo'its energy osiiy from the other $033 16; siibstontiaiiy described.

Signed by me oiilmozsigo oouilty of flooii,

55mm of Hinois, uhis .it-h do of November WILLIAM W. UEAN.

i i itnoL-ses 

